Apparently, advanced tortoises evolved multiple times: the high-domed shells and columnar, elephantine feet of current forms are specializations for terrestrial life that evolved __________ on each continent.
1. independently
2. interchangeably
3. paradoxically
4. simultaneously
5. symmetrically
1번이 답입니다. 나머지 오답 분석하고 있는데 4번이 왜 안되는지는 명쾌하게 잘 모르겟어요! 조언 부탁드립니다.